Date: Sun, 16 Mar 2003 22:00:05 +0100 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Bakul Shah <bakul@bitblocks.com> Cc: arch@FreeBSD.ORG Subject: Re: memcpy() with specified direction of copying ? Message-ID: <9531.1047848405@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 16 Mar 2003 12:52:10 PST." <200303162052.PAA05328@goliath.cnchost.com>
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In message <200303162052.PAA05328@goliath.cnchost.com>, Bakul Shah writes: >> Is there any standard which has provided an api for mandating the >> direction of copying from a memcpy() like function ? >> >> As I read our man-page, there is no way to know of memcpy() copies >> from the start and forward or from the end and backward through the >> two areas. > >The direction is not even relevant for memcpy and if the >source and destination overlap, the behavior is undefined. >Use memmove() for overlapped src and dst, but if you want the >direction reversed for some other reason you're on your own. Well, in my case it is a matter of shared memory where the order in which I snapshot a data structure is critical for detecting integrity issues. I'll roll my own. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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